Fan-fan drive assembly

Abstract

A plastic fan configured for attachment to a fan drive in a manner in which cooling air will be promoted to flow from the rear of the fan drive across the rear fins of the fan drive and through the blades of the fan. The flow of air across the rear fins increases heat dissipation from the fan drive. The fan has a plurality of radially extending circumferentially spaced blades secured to an axially extending hub portion. The hub portion is configured to be radially spaced from the fan drive to define an annular passage. Further, the front edge of the hub portion is spaced rearwardly from the forward portion of the rear fins of the fan drive to define a slot for cooling air to flow substantially unrestricted through the annular passage and to the blades of the fan.

What is claimed is: 
     
       1. A fan-fan drive assembly for cooling the prime mover of a vehicle comprising: (a) a fan rotatable about an axis and made of plastic, said fan including 1. an axially extending annular hub portion having an inner circumferential surface, a front edge lying in a generally radially extending plane, and a rear edge, and   2. a plurality of radially extending fan blades secured to said hub and each having a front edge lying in a generally radially extending plane and a rear edge;     (b) fan drive means to rotate said fan about said axis, said fan drive means including 1. a front face,   2. a rear face axially spaced from said front face and having a plurality of radially extending cooling fins each terminating at a forwardly located radially outermost portion that lies in a generally radially extending plane, and   3. an outer circumferential surface configured to be fit within and radially spaced from said inner circumferential surface of said fan to define an annular passage between said inner and outer circumferential surfaces; and     (c) means securing said fan in axially fixed encircling relationship to said fan drive to locate said plane of said outermost portion of said rear fins forwardly of said plane of said front edge of said hub and to define said annular passage.   
     
     
       2. A fan-fan drive assembly according to claim 1 wherein said hub encircles a portion of said rear fins. 
     
     
       3. A fan-fan drive assembly according to claim 2 wherein said rear edge of said hub lies axially rearwardly of said rear fins of said fan drive. 
     
     
       4. A fan-fan drive assembly according to claim 2 wherein said plane of said front edge of said blades lies axially forward of said plane of said outermost portion of said rear fins. 
     
     
       5. A fan-fan drive assembly according to claim 4 wherein said rear edge of said blades and said rear edge of said hub portion lie substantially in a radially extending plane. 
     
     
       6. A fan-fan drive assembly according to claim 4 further including front radially extending fins located on said front face and having a front edge lying in a generally radially extending plane. 
     
     
       7. A fan-fan drive assembly according to claim 6 wherein said plane of said front edge of said front fins is located axially forward of said plane of said front edge of said blades. 
     
     
       8. A fan-fan drive assembly according to claim 1 wherein said securing means include an annular spider made of metal and having a plurality of circumferentially spaced openings located adjacent said rear fins of said fan drive to allow for the flow of air from the rear of said fan-fan drive assembly to said rear fins. 
     
     
       9. A fan-fan drive assembly according to claim 8 wherein said spider is releasably secured to said fan drive and is rigidly fixed to said hub portion of said fan. 
     
     
       10. A fan-fan drive assembly according to claim 1 wherein said fan drive is a temperature responsive viscous fan drive having a temperature sensing element on said front face. 
     
     
       11. A fan-fan drive assembly according to claim 10 further including front radially extending fins located on said front face and having a front edge lying in a generally radially extending plane that is located axially forward of said plane of said front edge of said blades. 
     
     
       12. A fan to cool the prime mover of a vehicle and be releasably secured to a fan drive that is rotatable about an axis and has a front face, a rear face axially spaced from said front face and including a plurality of radially extending cooling fins each terminating at a radially outermost portion that lies in a generally radially extending plane, and an outer circumferential surface, said fan comprising: (a) an axially extending annular hub portion made of plastic and having an inner circumferential surface that is configured to encircle said outer circumferential surface of said fan drive and define therewith an annular passage between said inner and outer circumferential surfaces, said hub having a front edge lying in a generally radially extending plane;   (b) a plurality of radially extending fan blades made of plastic and secured to said hub, each blade having a front edge lying in a generally radially extending plane that is located forwardly of said plane of said front edge of said hub; and   (c) annular spider means made of metal and rigidly secured to said hub and adapted to be releasably secured to said fan drive to locate said plane of said front edge of said hub portion axially rearwardly of said plane of said outermost portion of said rear fins and to define said annular passage between said inner and outer circumferential surfaces.   
     
     
       13. A fan according to claim 12 further including a plurality of spaced openings in said spider.